Ignition system



June 23, 1953 J. F. PL JTNAM 2,643,284

IGNITION SYSTEM Filed Feb. 9, 1950 4 Sheets-Sheet 2 m \nven'tor" JoHN FT pUTNAM-OECEZASED By E.H.Pu+NAM,AoM|-|51-nm-Rm bYiw/dg AT TO? N EY- June 23, 1953 J. F. PUTNAM 2,643,284

IGNITION SYSTEM Filed Feb. 9, 1950 4 Sheets-Sheet s lllH o inventor JOHN F'. wrNAMpzczAseo 5 ,E.H. PUTNAM.ADMINI5TRATR1X June 23, 1953 J. F. PUTNAM 2,643,284

IGNITION SYSTEM Filed Feb. 9, 1950 4 Sheets-Sheet 4 Inventor JOHN F? Pu-r NAMJDECEASED ATTOE NEY.

Patented June 23, 1953 IGNITION SYSTEM John F. Putnam, deceased, late of Westhampton, Mass, by Eleanor H. Putnam, administratrix, Westhampton, Mass., assignor to American Bosch Corporation, Springfield, Mass, at corporation of New York Application February 9, 1950, Serial No. 143,174

' 4 Claims. 1

This invention relates to a new and improved ignition system for jet engines and has particular reference to such an ignition system which is relatively lightweight, simple and compact but yet provides high spark energy.

An object of the invention is to provide a new and improved ignition system for jet engines which system provides a condenser discharge type of ignition or spark, that is, a high energy, short duration discharge or spark for each individual discharge with a relatively high repetitive rate.

Another object of the invention is to provide such an ignition system wherein the coil and vibrator are positioned at a sufficient distance from the engine to avoid damage thereto by heat.

Another object is to provide a new and improved rectifying means and a new and improved method of assembling the same.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings. It will be understood that changes may be made in the details of construction and arrangement of parts shown and described, as the preferred form of the invention has been given by Way of illustration only.

Referring to the drawings:

Fig. 1 is a schematic diagram of the ignition system of the invention;

Fig. 2 is a top or plan View of the ignition system assembly showing the condenser and gap assembly with the cover removed;

Fig. 3 is a side View of. the assembly shown in Fig. 4 is a top or plan view of the coil and vibrator unit with the cover of the coil housing removed;

Fig. 5 is a sectional view taken on line 5-5 of Fig. 4, looking in the direction of the arrows; and

Fig. 6 is an end view of the vibrator in the coil and vibrator unit shown in Figs. 4 and 5.

Referring more particularly to the drawings wherein similar reference characters designate corresponding parts throughout, the invention consists broadly of an induction coil-vibrator assembly designated generally at 10, whose high adapted to be connected to a source of power such as battery II by lead Ha, and is also connected to the capacitor and gap unit [2 by lead 13, and

The induction coi1-vibrator assembly 10 is said capacitor and gap unit I2 is connected to ignitor plug l 4 by lead IS.

The induction coil-vibrator assembly I0 consists of a vibrator unit consisting of a pair of vibrator contacts [6, across which is the .3 mid. condenser H, and the compound wound vibrator coil I8 on laminated core i811, and which contains both series winding I81) and shunt winding [8a which is grounded at [9 and which unit is in housing 20 which is attached to induction coil housing 2 I. The series winding 18b of coil I8 is connected to primaryZZb of ignition coil by lead I811.

The induction coil and rectifier unit consists of an ignition coil 22 on laminated core 22a, and said coil is connected to the vibrator and said coil comprises primary 22b and secondary 22c and is surrounded by a plurality of selenium rectifier stacks 23 connected in series and of suificient number to provide a 10 kv. rectifier.

The rectifier stacks are insulated from each other by insulation 24 and are also insulated by insulation 25 and it will be noted that as shown in Fig. 4, the insulation 25 is graded and increases as the voltage increases in the system. The rectifier has an inverse peak rating of 50 k. v. p.

The capacitor or condenser assembly I2 is contained in housing 26 and consists of a .0025 mfd. energy discharge condenser 21 and sealed discharge series gap 28 with a break down voltage of from six to ten k. v. p. and which is connected to standard jet igniter plug M by lead I5. The condenser 21 consists of a plurality of sections mounted on glass rods 29 and 30 and is connected to lead l3 by lead 3| and to discharge gap 28 by lead 32.

The system is designed to operate from a 12 to 32 volts D. C. supply with an average current of 1.5 amperes at 24 volts.

It is pointed out that the system is designed for negative ground only.

The induction-coil vibrator and selenium rectifier are packaged separately from the capacitor and series gap for the following reasons:

1. The lead connecting the capacitor to the ignitor plug should not exceed three feet to retain the steep wave front of the voltage; and

2. The condenser and series gap are composed of glass and metal only so that high temperatures can be withstood by them, whereas the coil and selenium rectifiers should not be exposed to temperatures in excess of degrees F.

The induction coil and selenium rectifiers are hermetically sealed in transformer oil and the condenser and gap are potted in suitable potting compound for physical support and prevention of high altitude flash over.

The covers of the condenser and gap housing 26 and the vibrator housing 20 may be fastened on by screws or the like in order to allow easy removal for inspection. If total radio quietness is desired, these covers should be soldered to their respective housings and a filter placed in series with the battery supply.

All terminals except the battery input terminal may be coated with a suitable ignition sealing compound or grease to assist the terminal scaling for high altitude operation.

In operation, the vibrator acts as a means to interrupt the flow of current through'the primary of the induction coil to produce high voltage impulses in the secondary of the coil, and to regulate the current to a fairly constant value over a wide range of battery voltages. The inherent current regulating feature of the vibrator assists in, maintaining the output over a wide range of input battery voltage.

The output of the coil secondary is rectified to charge the capacitor .to a high voltage. The capacitor is isolated from the ignitor plug by the series gap during the charging period as, otherwise, leakage across the ignitor plug might prevent the capacitor from being charged.

When the voltage across the capacitor is high enough to break down the series gap and igniter plug gap, a high energy spark is produced at the ignitor plu which discharges the capacitor, oompleting one cycle of operation.

The. cycle is rapidly repeated andthe repetition rate of this cycle of operation is dependent.

upon the battery voltage, being lower at low voltages.

The maximum sparking rate at 28 volts is approximately 6000 sparks per minute and at volts the rate is approximately 1200 per minute, the rate being somewhat variable due to random voltage breakdowns of series gap and ignitor gap.

In the system described, the capacitor is designed to withstand charging and discharging to 25 k. v. p. Maximum energy available per pulse is approximately 300 mi. when the capacitor is discharging from 25 k. v. p. through the series gap From the foregoing it will be seen that new and improved means have been provided for obtaining all of the objects and advantages of the invention.

Having described the invention, What is claimed is:

1. In a device or the character described, a pair of attached housing portions, a vibrator in one of said housings and an ignition coil in the other of said housings, a rectifier in said housin for said ignition coil, said rectifier consisting of a plurality of stacks or sections inspaced relation surrounding said coil and connected in series and insulation for said stacks, said insulation being graded so that it increases as the voltage increases in the system.

2. In a device of the character described, a pair of attached housing portions, a vibrator in one of said housings and an ignition coil in the other of said housings, a rectifier in said housing nected in series and insulation for said stacks,

said insulation being graded so that it increases as the voltage increases in the system.

3. A coil and rectifier unit for ignition systems comprising, a housing, a coil in said hous-= ing, a plurality of rectifier stacks surrounding said coil, said rectifier stacks being connected in. series, insulation for said stacks and insulating said stacks from each other, said insulation being graded and increasing as the voltage increases in the system, said housing being oil filled and hermetically sealed.

4. A coil and rectifier unit for ignition systems comprising, a housing, a coil in said housing, a plurality of spaced selenium rectifier stacks surrounding said coil, said rectifier stacks being connected in series, insulation for said stacks and insulating said stacks from each other, said insulation being graded and increasing as the volt-- age increases in the system, said housing being oil filled and hermetically sealed.

ELEANOR H. PUTNAM, Administratrim of the estate 0 John F. Putmcm,

deceased.

References Cited in the file of this patent UNITED STATES PATENTS 

